Research into about insulators, the resistance of which varies according to an externally applied voltage, has been actively performed. In particular, the abrupt transition in a metal-insulator transition (MIT) material from an insulator to a metal has been researched through experiments (Hyuntak Kim, et. al., New Journal of Physics, vol. 6, p 52, 2004). An MIT material can be fabricated as a device having two terminals or three terminals by being deposited on a substrate and forming electrodes, and the MIT device can be applied to various electronic devices. For example, a patent disclosing an application of an MIT material as a field effect transistor (FET) has been registered (U.S. Pat. No. 6,624,463 B2, US registered patent, Oct. 23, 2003, Hyuntak Kim et. al.).
An MIT device shows a characteristic that an electric current increases abruptly and discontinuously (or a resistance reduces rapidly) when a voltage applied to the MIT device reaches a certain level (hereinafter, referred to as MIT generation voltage) or higher, and is transited from an insulator status to a metal status. The electrical characteristics of MIT devices can be applied in various ways and MIT devices can be used in various electric and electronic devices. However, there has been no instance of applying an MIT device to an oscillation phenomenon.
In this regard, research into oscillation characteristics of the voltage and current has been performed. That is, the oscillation characteristics of the voltage and current that is referred to as a Gunn effect in Group III-V semiconductor materials has been reported, and the oscillation has been described as being generated by a mobility of electric charges.
In addition, in a field of semiconductor oxides, when a circuit is constructed by connecting a material such as K03MoO3 and a resistor in series and a direct current (DC) voltage is applied to the circuit, an oscillation occurs in the electric current of the circuit. This phenomenon has been reported as being generated by a sliding motion of a charge-density wave. This oscillation characteristic is generated a low temperature around 20K, and the oscillation frequency is changed according to a magnitude of the applied voltage.
Recently, the oscillation of an organic material has also been reported, that is, when a circuit is constructed by directly contacting a conductive organic salt material, a resistance of which is greatly changed according to an external applied voltage, to a thin film resistor and an external voltage of a certain degree or higher is applied to the circuit, an oscillation occurs in the current flowing in the circuit. The change in the resistance of the conductive organic salt is caused by a change in a charge ordering.
The oscillation of the Group III-V material and the organic material is caused only when the external voltage is applied to the material, and a waveform of the oscillation is a sinusoidal wave that is continuously changed. In addition, the oscillation of the oxide material only occurs at a low temperature, while the oscillation frequency can be controlled. Moreover, the oscillation frequency generated from the oscillation device using the organic material is very low.
In addition, in order to realize a conventional oscillation device, for example, an inverter or an oscillator, an amplifier, a switching circuit, and a feedback loop should be constructed. In order to form the amplifier, the switching circuit, and the feedback loop, various electronic devices such as a transistor, a capacitor, and an inductor are required in addition to the resistor. Therefore, there is a limitation in minimizing a conventional oscillation device using the various electronic devices described above, and fabrication costs of the oscillation device also increase.